Ophthalmoscope



(No Model.)

J.- T. BRAYTON.

OPHTHALMOSGOPE. No. 591,617. Patented Oct. 12,1897.

Tug. Z.

UNITED STATES PATENT OFF E.

JAMES T. BRAYTON, or CHICAGO, ILLINOIS.

OPHTHALMOSC'OPE.

SPECIFICATION forming part of Letters Patent No. 591 ,617', dated October 12, 1897. Ap li atio as November 24,1896. Serial No. 613,327. (No'modelJ To all whom it may conce n.-

' Be it known that 'L-JAMES T. BRAYToN,a

citizen of the United States, residing at Chi cago, in'the'county of Cook and State of Illinois, have'invented certain new and useful Improvements in Ophthalmoscopes, which are fully set forth in the following specification, reference being had to the accompanying drawings, forming-a part hereof, and in which Figure 1 shows my said device in front elevation. Fig. 2 shows the same in edge elevation. Fig. 3 shows the same in rear elevation. Fig. 4 shows the main disk in elevation as seen when in use. Fig. 5 shows the secondary disk as seen when in use. Fig. 6 shows the sub disk or sector in its front view. Fig. 7 shows the reverse of Fig. 4. Fig. 8 shows a section of Fig. 4 on plane 1 1. Fig. 9 shows a section of Fig. 5 on plane 2 2. Fig. 10 shows the naked holder. Fig. llshows a plan and central edge elevation of a spring-washer on the central hub or center of the instrument. Like letters of reference denote like parts. The object of my invention is to produce an ophthalmoscope of superior construction and a more simplified and easier method of notation and other advantages. To attain said desirable ends I construct my said new and improved instrument in substantially the following manner, namely:

Upon a handle provided with a fixed plate a, provided with a disk center and disk hub Z and peep-hole c, is mounted a main disk cl, provided with a large central opening to fit and turn freely on the larger part b of the hub. In said disk 1) are also ten openings, of which nine are provided with suitable lenses numbered radially underneath and respectively 1 2 3 45:6 7 8 9. The remaining opening, being left as a peep-hole, is marked with a zero or cipher, and radially within said set.

of numbers is another set of numbers with its zero under the aforesaid number 9 and its number 9 under the aforesaid zero, its number 8 under the aforesaid number 1, and so on, decreasing in the same direction in which said other set of numbers increases. The edge of said disk (1 is milled for hold in turning it, and near its edge, on the near side, (that side which faces the user,) is a rim d, within which lies a partially-rotatable disk (which may herein be called a sub or secondary disk) provided with a smaller opening to fit theouter end 6 of the hub and (here) five peripheral openings of corresponding size and axially coincident with as many of any of the said ten holes of the disk'd, whereof the central hole is left a blank or peep hole and the remaining ones provided with suitable lenses. On lines radial with said five peripheral holes are two circles of holes, the outer circle in a set of three with numerals 2 and l preceding them and a set of two holes with the numeral 1 between them coincident with the inner circle of said numerals and the outer set of holes coincident with the outer circle of numerals on the disk at. Ten countersunk notches e, radially under the holes in the disk d, catch in a short spur e on the plate a, so asto bring each of said holes and lenses to a stop coincidently over the peep-hole c of the plate a, and correspondingly there are five such countersunk notches e in the secondary disk 9 on the side facing theuser held bya spur e in the back h, held to the handle by a screw h and the disk-headed center screw 7L2. A peg f forms .both a handle and a stop to the disk g, its rotation being arrested by the shoulders 2' 1', formed on the edge of the back h. A sub disk or sector j, with three holes coincident in position with the holes in said main and secondary disks, is placed on the hub 11 andv held by a screw 6 in front of the plate a, and is provided with a suitable lens on each side of the blank central hole with legs k on each side of the mirror-bracket Z, spread to allow a range of rotation sufficient to bring said three holes coincident with the hole a. It is also provided with a countersunk notch 6 to stop the central hole on-the spur 6 over the hole 0 and is operated by peg-handles f. A mirror m is held in the bracket land is provided with a central peep-hole axially coincident with the hole 0.

In Fig. 1 the sector j is in central position, covering with its legs the numerals 50, marked with the signs f-and respectively. The spring-washer, Fig. 11, holds the disks yieldingly to the plate a and to each other. A V-shaped notch 'v is cut from the My arrangement of the lenses in the parts (i g j is substantially as follows, namely: In the main disk (1 is placed a concave lens of one dioptric in power denoted by the numeral 1 under it. Over the denoting number 2 is placed a similar lens of the power of two dioptrics, and so 011 to the ninth hole, which has a lens of the power of nine dioptrics. The secondary disk g is provided with two concave lenses, of which the one next to the peep-hole is a minus-ten, (marked 10,) and next to it is a minus-twenty lens, (marked -20,) and on the opposite side of the peephole is a plus-nine lens, (marked +9,) and beyond that is a pl us-nineteen lens, (marked +19.)

It is obvious that the range or power of my instrument could be increased by placing a minus-thirty lens beyond the minus-twenty lens and a plus-twent-y-nine lens beyond the plus-nineteen lens, and that corresponding holes would have to be made in the secondary disk to read the figures through them on the main disk, the utmost reading of the instrument thus becoming plus twenty-nine and minus thirty-nine, and so on.

In the segment j, I place a minus lens of one-half dioptric on the left or minus side of the secondary disk, and on the other side of the peep-hole corresponding to the plus side of the secondary disk I place a convex or plus lens of one-half dioptric power, it being a well-known fact that a concave will neutralize a convex lens of the same power or so much of differing opposite lenses as will leave a result equal to the difference of their powers.

By means of the combinations shown herein minus or concave powers from one to twentynine and plus or convex dioptrics from one to nineteen are obtained, and by means of the said two half-dioptric lenses every power possible with the lenses of said two disks may be increased or diminished a one-half dioptric.

\Vhat I claim is 1. The combination with a disk provided with a series of lenses with like signs, Varying by single dioptrics, of a disk with two opposed series of lenses whereof one series begins with plus nine and the other series with minus ten, each starting near the same radial point and running in a direction opposite to the other set of lenses, and each lens axially coincident with the series of lenses in said former plate,a central stud for said disks, means to axially coincide and hold any of said contrary-signed with any of said first series of lenses, a concaved peep-holed mirror axially coincident with said lenses when ranged for use, substantially as specified.

2. The combination with two superimposed separately-rotatable disks and a series of like lenses varying by single dioptrics in one of said disks and a series of lenses beginning with plus nine and increasing by powers of ten dioptrics on one half of the other disk, and a series of lenses beginning with minus ten and increasing by powers of ten dioptrics on the other half of said disk, of a sector provided with a minus lens having a fractional dioptric power on one side of its center and a plus lens with a fractional dioptric power on the opposite side of the center of said sector and means to superimpose any of said lenses in said several disks and register their etfect, substantially as specified.

3. The combination with two superimposed separately-rotatable disks and a series of like lenses varying by single dioptrics in one of said disks and radially under them the numerals 1, 2, 3, 4, 5, 6, 7, 8, 9, corresponding to the dioptric value of said lenses, and radially within said numerals a second circle of numerals with a cipher under the said numeral 0, one under 8, and so on, running in the opposite direction to the numbers of the outer circle, of a series of lenses beginning with plus nine and increasing by powers of ten dioptrics on one half of the other disk and a series of lenses beginning with minus ten and increasing by powers of ten dioptrics in the other half of said disk and a series of openings radially under said minus lenses and coincident with said outer circle of numerals and a series of openings radially under said plus lenses and coincident with the said inner circle of numerals, the openingsin said circles provided with numbers which form a part of the register read with the numeral exposed by said openings, and means to superimpose any of said lenses, and to read said registers, substantially as specified.

l. The combination with a disk provided with a series of lenses with like signs, varying by single dioptrics, of a disk with two opposed series of lenses whereof one series begins with plus nine and the other series with minus ten, each starting near the same radial point and running in a direction opposite to that of the other, and each lens axially coincident with the series of lenses in said former plate, a central stud for said disks, means to axially coincide and hold any of said contrary-signed with said first series of lenses, a fixed peep-hole and a peep-holed mirror, each axially coincident with said lenses when ranged for use, substantially as specified.

JAMES 'l. BRAYTON.

\Vitnesses:

WM. ZIMMERMAN, E. G. JACKER. 

